In one known form of frame for releasably holding a mop head, the frame has an oblong planar form for a correspondingly shaped mop head which lies against the underside of the frame. The frame is divided into two laterally opposed sections which overlap at the central region of the longer side of the frame and are pivoted to each other by a hinge near to, but off-set from, the centre of the longer side of the frame. When a manual catch is released, the frame sections can pivot relative to each other to a collapsed angular configuration for putting on and removing the mop head. On the upper face of the mop head, at each end of its longer sides, there is a pocket in which the ends of the frame fit when in its planar configuration. The mop head simply falls from the frame when the frame sections are collapsed and lie at an angle to each other. To take up the mop head again, the ends of the frame sections are slipped into the pockets before they are pivoted once more to their planar configuration to hold the head on the frame.
When using a mop, the mop head must be wrung from time to time to remove moisture from it. In this known form of mop it is necessary for the planar frame, with the mop head on it, to be placed between a pair of pressure plates. This is not a very efficient method of wringing, because the presence of the frame impedes the escape of moisture and makes it impossible to apply an even pressure to the material of the mop head. Moreover, the intensity of pressure that can be generated is limited because the force is applied over the entire area of the frame and mop head.